<ul>
  <for|comment, i| of=input.comments>
    <const/id=`${input.path || "c"}-${i}`/>
    <let/open=true/>
    <li id=id hidden=!open>
      <span>${comment.text}</span>
      <button onClick() { open = !open }>
        ${open ? "[-]" : "[+]"}
      </button>
      <if=comment.comments>
        <comments comments=comment.comments path=id/>
      </if>
    </li>
  </for>
</ul>